Speed trouble

[Guest jeffpelgrims]

Hello to all of you :)Before post this message I read the sticky post but I did'nt find a solution for my trouble.I've a little speed trouble right now, I'm at FL360 and at the VNAV page of my FMC the Econ SPD is .833 that's correct. But the autopilot don't want to go to this speed, It wants 281 kts (this speed is showing right now on the PROG page).My question is simple, how to tell the AP to use the econ spd and not 281 kts who makes my plane go to the red...Okay just a new thing is happened, the speed is coming to normal for a short time then the 281 kts come again... It looks like the computer jump batween this two speed, maybe a new bug for you...Hum I just pushed the P button to resume my flight and 281 kts still choose... btw 281 is the lim spd.I'll check this during all the flight and tell you is something new happen.Thx a lot :)

[de Lattre WGA 0]

Hello,See my comments after the ++++>Hello to all of you :)>>Before post this message I read the sticky post but I did'nt>find a solution for my trouble.>>I've a little speed trouble right now, I'm at FL360 and at the>VNAV page of my FMC the Econ SPD is .833 that's correct. But>the autopilot don't want to go to this speed, It wants 281 kts>(this speed is showing right now on the PROG page).+++At this altitude the AP is not following speed but Mach number. So in the cruise VNAV page you should have speed/Mach number IE for example 260/.833Question, are you in VNAV mode or speed mode, or even Mach selected mode?>>My question is simple, how to tell the AP to use the econ spd>and not 281 kts who makes my plane go to the red...++++If you activate LNAV and Vnav, you should be set up.>>Okay just a new thing is happened, the speed is coming to>normal for a short time then the 281 kts come again... It>looks like the computer jump batween this two speed, maybe a>new bug for you...+++ I bet you are using a weather prog, or the default FS. If using an external weather prog, that is because you are experiencing temp variation, and in the case the FMC is reacting accordingly to the temp variation please let us know.>>Hum I just pushed the P button to resume my flight and 281 kts>still choose... btw 281 is the lim spd.+++What is your cost index? if you entered any.>>I'll check this during all the flight and tell you is>something new happen.>>Thx a lot :)Cyrille de LattreAsus P4P800/PIV 3 Ghz/2 Giga DDRAMATI X800 GT 256 MegWin XP SP2 / FS9.1 PSS Beta tester

[Guest jeffpelgrims]

>Hello,>>See my comments after the ++++>>>>>Hello to all of you :)>>>>Before post this message I read the sticky post but I did'nt>>find a solution for my trouble.>>>>I've a little speed trouble right now, I'm at FL360 and at>the>>VNAV page of my FMC the Econ SPD is .833 that's correct. But>>the autopilot don't want to go to this speed, It wants 281>kts>>(this speed is showing right now on the PROG page).>>+++At this altitude the AP is not following speed but Mach>number. So in the cruise VNAV page you should have speed/Mach>number IE for example >260/.833Correct>>Question, are you in VNAV mode or speed mode, or even Mach>selected mode?>>>>>My question is simple, how to tell the AP to use the econ>spd>>and not 281 kts who makes my plane go to the red...>>++++If you activate LNAV and Vnav, you should be set up.LNAV and VNAV are activated>>>>Okay just a new thing is happened, the speed is coming to>>normal for a short time then the 281 kts come again... It>>looks like the computer jump batween this two speed, maybe a>>new bug for you...>>+++ I bet you are using a weather prog, or the default FS. If>using an external weather prog, that is because you are>experiencing temp variation, and in the case the FMC is>reacting accordingly to the temp variation please let us>know.>I use ASV but without online update and this did'nt happened before>>>>Hum I just pushed the P button to resume my flight and 281>kts>>still choose... btw 281 is the lim spd.>>+++What is your cost index? if you entered any.80>>>>I'll check this during all the flight and tell you is>>something new happen.>>>>Thx a lot :)>>>Cyrille de Lattre>>Asus P4P800/PIV 3 Ghz/2 Giga DDRAM>ATI X800 GT 256 Meg>Win XP SP2 / FS9.1 >PSS Beta testerThx Cyrille, I found a little fix, I changed the econ spd to .830 and then to .833... now everything is fine...

[de Lattre WGA 0]

Hello,Regarding your jumping speed due to temp variaiton, this definitely something to deal with ASV. Please make sure you have the latest service update.Also you have to know that I did experiment this a few times with ASV, rarely but it did, and reloading the weather did cure the problem.I strongly suggest that you use the online updater, because it may solve this kind of prob when there are incorrect data.Lnav and vnav engaged will automaticaly use the econ speed in the vnav page.Basicaly when the econ speed says 281/.833, i means when your indicated airspeed reaches this mach number, it will automaticaly switch to mach number, and then the higher you are climbing, the lower your indicated airspeed will be while your mach number will remain the same. It is called constant mach climb. Of course, this is where step climb jumps in.Now If I understood correctly what you said, IE at FL360 with CI 80, the VNAV and LNAV is engaged it brings you in anoverspeed situation.If that assumption, is correct, it can't be the MCDU that put you in this situation, with out an external eventThis event can be double:-Pilot induced.-Weather induced.I use a CI of 99 almost all the times, and I have never been in this situation.As I have a doubt, IE i believe it is both (pilot and weather), no offense taken,please it was not meant that way, I would like you to do something for me. -1/ be sure to have loaded the aircraft correctly, take a screen shot of the load edit, or use the same load as the time you had the problem,then do the flight again with the same weather if you have saved it, then report if you have the same prob. Please if you can take screenshots. -2/ do the same flight as above with out the weather.Finaly report to me.Cyrille de LattreAsus P4P800/PIV 3 Ghz/2 Giga DDRAMATI X800 GT 256 MegWin XP SP2 / FS9.1 PSS Beta tester